While you are deploying your code with the Circle ci pipeline and if your deployment is stuck without deployment success and if the error will be thrown like this,
Deploy locked by ci.
Execute “deploy:unlock” task to unlock
You can fix this issue by manually deleting deploy.lock from your server.
In my case, It was a Sonassi server and You have to go SSH with your project root,
Just Delete the deploy.lock file from here and start deployment again to fix the issue.
Whenever a deployment starts it creates a lock file to naturally stop against multiple deploys being done since a deployment can touch the database. You need to manually remove this file to run the deployment again.
When Deployment started, https://github.com/deployphp/deployer/blob/master/recipe/common.php#L137 It can already lock the current deployment before the release is completed.